The downside to a class system is that potential is not reached,. True, but the same can be said now. As a rule of thumb it is still hard to jump 2 social classes in a generation.

The Luddites were the first to realise that machines negated the need for many people in an economy.
The french aristocracy had the same problem in that although they were the "top", merchants still earned more than they did.

Decent A levels (not the shite we've got in the UK at the moment should allow people to perform high tech jobs. Then there are a limited few who need more which is offered by pure universities.

If you think 10% is too low, then sandwich degrees could be for the other 30% who will be accredited after 5 or so years on the job. Like a modern day apprenticeship.

I think that broad sorting can start at 14. At that age many could go and become apprentices at skilled manual vocations. By the time the are 16 they'd be amazing mechanics, not with a certificate stating they are rubbish at French. Of course they are going to be people who don't fit the mould. We currently seem to need to retrain masses of people in the basics even with the long education system. I feel this method would require far less.

No, I don't currently work - a very sore point that the Powers That Be are dragging their feet to correct (of course the paperwork should have been done over 2 months ago - but it just isn't...)

Concerning parent's complaining, one lecturer at a uni said that they have to give students a 2:1, else the parents complain! I hope that this only is the case at the worst universities.